Is a Corsair HX650 enough for dual 5870's?

gregl342

gregl342

gregl342

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I have just bought a second 5870 off of ebay for a tidy £130 and before hand did have a look around a few forums with people asking the same thing, however could not fathem a definite conclusion. I am running an ex58-ud5 board with an i7 920 at 3.8ghz at 1.31v 6gb ram 1tb hdd and 120gb SSD. The psu has a single 12v rail, with 52A on it. Also AMD state that to crossfire these gpus 600w+ is recommended. A few people said a minimum of 55A and i was wondering how precise this is and whether i could get by with my solid corsair unit? If not i could fork out for an 850w silverstone unit but not for a few weeks as i havnt the money so would my hx650 survive that length of time? Thanks in advance, Greg.
 
Well that means the PSU will be between 70-75% when gaming. I also plan to overclock the card to 950MHz core clock with afterburner (i have flashed my xfx card to an msi bios for unlocked voltage and plan to do so with my new one (powercolor)) so that will probably put it to around 80-85% usage. This really isnt good for a PSU. Your are supposed to have it around 60% so would this cause a PSU failure in the long term? Regards.
 
Well the HX series is rated to provide the max wattage continuously, so you should be fine. The whole 60% number comes from PSUs not designed to supply their rated wattage 24/7 (AKA cheaper units). You are also covered by a 7 year warranty on the unit. Assuming it isn't really old it should be up to the job.

I'd say go for it, if you get some instability just dial back the overclock but I'd be suprised if you do.
 
Okay but it will mean that it wont run as efficiently as the more power used makes the rails heat up and then the efficiency goes down when heat is involved. Ahh well im sure it will run fine. The PSU is around 1.5 years old so it isnt ancient by any means.
 
Honestly buying a huge wattage PSU just to get a system in the slightly more efficient band is a false economy, unless your system is at 100% load 24/7 (Folding@Home etc). You are talking about 1-2% so it would take ages to make back the extra you paid.

Obviously if you get stability problems then sell the HX650W and get something more powerful, but you won't know unless you try.
 
The corsair, or any good PSU can certainly go much higher that 60% full load. It efficiency starts to peak around 60%, but will stay high until it can't provide no more (well over 700W load, which obviously is not recommended). 85% would be my recommended max. If you measured 'at the plug', then that is actually 85% of 85% :) So you have quite a margin. 650W consumption at the plug means 550W actual load on the PSU.

The problem is the PCIE connectors. You may have to use molexes to connect the card to the PSU. Duno how many conectors come with the HX650.

http://www.anandtech.com/bench/Product/163

So 500W consumption heavy stress (600W Furmark). I think you'll be fine really. If you want, get a power monitor plug thingy (I wish OcUK sold these) to monitor the power consumption. They're about £15, and IMO useful to have in a house anyway.
 
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Just be aware what it pulls at the wall is not what the unit itself is supplying, which can make the plug-in energy monitors mis-leading. They are however great for keeping an eye on what the unit is consuming in kWH.
 
Okay well i think this clears things up, i will be just fine i reckon :) oh and the HX650 has 4 6+2 pin connectors so its definitely enough for 2 5870s (two 6 pins each)
 
Installed my second card now and currently running furmark with both cards at 950MHz and i7 at 3.8GHz. So far so good :D (PSU doesnt even feel hotter, hasnt increased fan speed or anything!)
 
gregl342 said:
Not exaggerating, i can post a pic if you like? Been an ongoing build for years :D
And how come only 4 lines of text? Why does it matter?
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The exaggeration was that it would "monster anything on the market".

The size of your signature matters because those are the forum rules.

If the Mods come across an oversized signature they'll just delete it.

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Ahh right, well i have changed it now :)
And i think its will monster anything i have thrown at it, metro 2033 at full settings at 2560-1440 50+ FPS! Pretty darn goof. Maybe if i was running eyefinity or something it may start to drop at ultra settings.
 
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